Rubber bushing



April 19 1949. k D. T. BRADLEY 2,467,548

RUBBER BUSHING Filed April 25, 1947 Patented Apr. 19, 1949 RUBBER RUSHING Dan T. Bradley, Shaker Heights, Ohio, assigner t to Harris Products Company, Cleveland, Ohio, a corporation of Ohio Application April 25, 1947, Serial No. 743,968

2 Claims. l Y

This invention relates to improvements in rubber bushings forming part of a pivotal connection.

One of the objects of the present invention is the provision of an improved annular bushing of rubber-like material adapted to be positioned between a central pintle and an embracing sleeve, together with means for applying compression at the outer lend of the bushing in such a manner that the compression of the rubber-like material is increased far beyond that previously considered possible.

Another advantage of the present invention ls that the manner of application of the compression to the rubber-like bushing prevents a swelling or escape of material between the compression member and the above mentioned sleeve, thereby making it possible to increase the clearance between the compression member and the sleeve.

Another object of the present invention is to provide an annular bushing of rubber-like material, as mentioned above, having an outer end face tapering outwardly and toward the center thereof, together with a compression member engaging said outer end face and generally conforming to the contour thereof whereby the lines of force resulting from the compression and extending at right angles to the end face of the bushing extend entirely within the connes of the embracing sleeve whereby certain valuable results are produced, as will presently appear.

Other objects and advantages of the present invention will be apparent from the accompanying drawings and description and the essential features thereof will be set forth in the appended claims.

-In the drawings,

Fig. 1 is a side elevational view of a spring suspension illustrating one use for my improved invention;

Fig. 2 is an enlarged iragmental sectional View taken along the line 2-2 of Fig. 1;

Fig. 3 is a view of the parts of Fig. 2 before compression is applied;

Fig. 4 is a diagrammatic view illustrating the lines of force within the bushing as compression commences;

Fig. 5 is a diagrammatic view illustrating the position of the lines of force Within the bushing upon the completion of compression; While Fig. 6 is a sectional view similar to Fig. 2 showing a modified l'orm of my device.

The use of compressed annular bushings in pivotal connections is well known as disclosed 2 in United States Patent 1,945,369, granted January 30,-1934, to Howard C. Harris. There was a limit to the pressure which could be applied to the rubber-like bushing of the said patented Harris connection and the compression members had to be spaced fairly close to the annular bushing sleeve as otherwise, the rubber-like material would escape between the conning surfaces. The present invention greatly increases the amount of compression which may be applied to the rubber-like material and greatly increases the possible dimension between the compression members and the sleeve embracing the bushing.

One use of my invention is illustrated in Fig. 1 as applied to the pivotal connection where the spring I Il is connected to the shackle II. As is customary in such cases, the spring I0 is provided at its end with a spring eye IIJa through which passes a pintle or bolt I2 for the purpose of securing the eye and shackle together. My improved bushing I3 of rubber-like material is adapted to be used in this location between the pintle and the embracing sleeve. The bushing comprises an annular body portion I3a and an outer end portion I3b which extends laterally beyond the sleeve I0a. The portion I3b is generally in the form of a thickened flange, as shown in Fig. 3 which extends beyond the internal diameter of the sleeve Illa. There is a shoulder I 3c where the ilange joins the body portion. The outer end face I 3d of the bushing tapers outwardly toward the center of the bushing as shown in the various views. This tapering eect may be a convex curvature or a portion of a truncated cone.

The members through which compression is applied to the ends of the rubber-like bushing, in this case the shackles II, are provided with concave recesses IIa which correspond in contour substantially to the end face I3d of the associated bushing. Compression is applied by screwing the nut I4 on the pintle bolt I2.

As viewed in Figs. 3 and 4, when the parts are placed in the position shown, there is a slight clearance between the body portion I3a of the bushing and the internal diameter of the sleeve Illa at the zone I5. This is exaggerated in the drawings because it is actually only a few thousandths of an inch. Preferably, two bushings are assembled end to end as shown on the sleeve I6 through the hollow center of which the pintle I2 passes. As clearly shown in Fig. 3, before the compression is applied, the rubber bushings extend laterally beyond the ends of the sleeve I 8. AS compression starts, the compression forces 3 Y have components directed as shown by the ai'- rows of Fig. 4. The lines of force within the bushing extend somewhat vas indicated by the broken lines. 'I'here areno compression forces exerted outside ofthe dash ling I'I as shown in Figs. 4 and 5, but compression might be extended as far as the dot-dash lines Il while still having the lines of force held entirely within the rubber bushing.` It will be noted that these lines of forcenormaltothecoactlngsurfaces Ila and lid pass through the plane wherethe fiangeiib Joins the body portion lla of the bushing wholly within the internal diameter of thesleeve` Ila. When the compression is completed as shown in Pigs.2and5,thelinesofforcenormaltothe coacting surfaces Ila and ,lid are still wholly confined to the rubber bushing and pass into device oi the present application this does not the body portion ila wholly within the confines of the sleeve lla and entirely ms the shoulder llc as clearly indicated in Fig. 5. At this time, the end of the bushing is ilush with the end of sleeve II.v :If necessary or desirable, a slight portion of the end face lid as indicated at Il may extend radially outwardly from'the end of tube I6 before the taper begins.

In vthe modification of` Fig. 6, I have shown a support for a torque tube 2l wherein a portion 4 tion of the bushing as described in connection with Figs. 4 and 5. I am thus enabled to increase the distance between the sleeve Ida and the compression member ii twenty-uve percent over that occur and full pressure is developed at the center oi'v the eye Na giving uniform and tight pressure against all bushing-connning surfaces.

What I claim is:

1. In combination, a` sleeve, a cylindrical mem- -ber positioned axially of said sleeve, an annular bushing of rubber-like material positioned between said cylindrical member and said sleeve,

of the tube and a sleeve I la are integrally formed to provide functionssimilar to the sleeve 'Ila of the ilrst described modication. A central pintle 2| is of bolt form and providedrwith a nut 22. The outer end faces of the rubber-like bushing 2l are convex outwardly as indicated at Na. These bushings are assembled end to end on `the pintle 2l between compression collars 2|.

These collars are provided' with concave surfaces 24a which conform generally to the convex end faces 23a of the bushings. When pressure is applied by threading the nut 22 on the pintle bolt 2i the collars 24 are urged toward each other and apply compression in the bushing 2l. There is very little swelling of the rubber at the points 25 during this compression operation because the lines of force normal to the surfaces 23a and Ila lie wholly within the rubber bushing and pass directly into the body of the bushing embracedby the sleeve 20. 29a. Here again. the principle is the same as that of the first described modifica# tion.

`'I'he rubber-like material of which these bushings are made is substantially incompressible and pressure is transmitted through the bushing material ln a similar manner to the transfer of pressure through. an incompressible fluid. It results from this fact that the pressure applied at theends of my improved rubber bushing is distributed through all portions of the bushing and. presses the rubber-like material firmly against all confined-surfaces. With my improved construction it is possible to greatly increase the pressure over that possible with the Harris pivotal connection patented in 1934, as mentioned above.

The improved bushing of the present disclosure y will run from three to four times longer than the above vmentioned patented Harris bushing under the same test conditions.

Referring to Fig. 2, it will be noted that the rubber-like material `swells outwardly `at the points 26 when compression is applied.` In the Harris patented bushing mentioned above, such swelling became excessive if the compression was increased to the degree which I utilize with my improvedbushing. I believe this swellingis decreased by my present invention because the lines of force are retained within the annular body porthe outer end face of said bushing tapering outwardly and toward the center thereof, a compression member engaging said outer end face and having a tapering face generally conforming to the contour of said bushing end face, there being a clear space laterally outside said bushing between said sleeve and said compression member beyond the tapering face thereof and means urgt ing said compression member inwardly to cause said bushing to press against all confining sur` faces, said end face and tapering face having engaging contours from which substantially all lines normal to said tapering face project entirely within the confines of the end opening of said Sleeve.

2. In combination, a sleeve, a cylindrical mem-- ber positioned axially of said sleeve, two annular bushings of rubber-like material having body portions positioned end to end between said cylindrical member and said sleeve, each of said body portions having an outer end portion extending beyond said sleeve and there provided with a thickened integral flange overlying the end of said sleeve, the outer end -face of each of said bushings tapering outwardly and toward the center thereof, a compression member engaging each said outer end face and having a tapering face generally conforming to the contour of said bushing end face, there being a clear space laterally outside said bushing between said sleeve and `compression member beyond the tapering face of the latter, means urging said compression members toward each other to cause said bushings to press against all confining surfaces, and each said end face and said associated tapering face having engaging contours from which substantially all lines normal to said tapering face project entirely within the confines of the adjacent end opening of said sleeve.

DAN T. BRADLEY.

REFERENCES crrnn The following references are oi' record in the file of this patent:

UNITED s'rATns PATENTS Hastings Sept. 13, 1932 

